Barnacle scale,Ceroplastes cirripediformisComstock (Homoptera: Coccidae), reached damaging levels in several groves In the Lower Rio Grande Valley of Texas during 1975.Metaphycus eruptorHoward was the most numerous primary parasite, althoughCoccophagus ochraceusHoward,Ammonoencyrtus californicus(Compere), and an unknown encyrtid were also recovered. Effectiveness of the primary parasites was apparently reduced by the hyperparasitesMarietta pulchella(Howard),Tetrasticus minutus(Howard), andCheiloneurus inimicusCompere. Parasitism by primaries varied from 4 to 31%, and that by hyperparasites 0.0 to 56%. Individuals per host varied from 1 to 22 for primaries and 1 to 9 for hyperparasites. A single incident was found in research plots of a possible association between increase in barnacle scale and use of dicofol. Because of the effective biological control, barnacle scale was scarce on Texas citrus during 1977.